1. Field of the Invention
The present invention relates to a component built-in module in which an electronic component such as a semiconductor and/or a circuit component is provided inside an electric insulation layer, and to a method for manufacturing the same.
2. Related Background Art
Recently, following the tendency of electronic devices toward high performance and compact size, it is increasingly demanded to achieve high density and improved function of circuit components. It also is demanded to provide a circuit-component-mounted module suitable for high density and improved performance. To mount circuit components at a higher density, wiring patterns are complicated increasingly, and hence, there is a tendency of wiring boards toward multi-lamination.
In the case of conventional glass-epoxy substrates, multi-lamination is achieved with a through hole structure that is obtained by drilling. This structure has high reliability, but wiring patterns provided thereon are limited since wiring patterns in different layers are connected using through holes. Furthermore, a semiconductor or a circuit component cannot be mounted at an area on a surface of the wiring board where the through hole is provided, and therefore, it is not suitable for high-density component-mounting.
Therefore, as a method for achieving high densification of circuitry, a multi-layer wiring board utilizing electric connection by inner vias is used also. The inner via connection allows the wiring patterns between large scale integrated circuits (LSIs) and components to be connected over the shortest distances, and also provides only necessary connections between wiring pattern layers, thereby facilitating the circuit component mounting. Furthermore, by incorporating circuit components in a wiring board, the component mounting efficiency is improved further.
However, the incorporation of circuit components and the connection of the same through inner vias may have a problem in reliability. The reliability of the inner via connection is influenced significantly by the ratio of a height of an inner via to a diameter thereof (i.e., aspect ratio=height/diameter). In the case where a circuit component is incorporated in a wiring board, an electric insulation layer having a height greater than a height of the circuit component is required, thereby necessarily causing an inner via to have a greater height. Therefore, to improve the connection reliability, it is necessary to increase the diameter of an inner via. However, an increase in the diameter leads to a decrease in the mounting density.
Therefore, it is an object of the present invention to provide a component built-in module that has high reliability and is suitable for high-density component-mounting, and a method for manufacturing the same.
A first component built-in module of the present invention includes: an electric insulation layer; first wiring patterns in a plurality of layers that are laminated with the electric insulation layer being interposed therebetween; at least one first inner via electrically connecting the first wiring patterns in different layers with each other; and at least one electronic component that is embedded in the electric insulation layer and is mounted on any one of the first wiring patterns in the plurality of layers. Herein, at least one of the first inner vias is present in a range that overlaps a range in which the electronic component is present in a lamination direction in which the first wiring patterns are laminated, and has a height in the lamination direction that is smaller than a height of the electronic component.
Here, in the present invention, xe2x80x9cheight of an electronic componentxe2x80x9d means a distance from an upper surface of a wiring pattern on which the electronic component is mounted to an upper surface of the electronic component. More preferably, it means a thickness of the electronic component itself. Furthermore, the term xe2x80x9coverlapxe2x80x9d herein means that the two concerned ranges overlap each other at least partly, and the ranges do not necessarily coincide with each other completely.
This configuration makes it possible to suppress a height of the first inner via provided substantially opposite to the electronic component in a direction perpendicular to the lamination direction of the first wiring patterns. As a result, even with a decreased diameter of the via, the degradation of reliability resulting from an increase in the aspect ratio is prevented. Therefore, it is possible to provide a component built-in module that has high reliability and is suitable for high-density component-mounting.
The first component built-in module preferably further includes a wiring board including second wiring patterns in at least two layers, and a through hole and/or a second inner via that electrically connects the second wiring patterns in different layers with each other. Here, the wiring board is embedded inside the electric insulation layer, and any one of the first wiring patterns in the plurality of layers and the second wiring pattern are connected electrically through an inner via.
This configuration makes it possible to provide a component built-in module suitable for high-density component-mounting, taking advantage of the high reliability of the wiring board. Further, since a generally used wiring board can be used, this leads to a decrease in production cost.
Next, a second component built-in module of the present invention includes: an electric insulation layer; first wiring patterns in a plurality of layers that are laminated with the electric insulation layer being interposed therebetween; at least one first inner via electrically connecting the first wiring patterns in different layers with each other; a wiring board including second wiring patterns in at least two layers, and a through hole and/or a second inner via that electrically connects the second wiring patterns in different layers with each other; and at least one electronic component that is embedded in the electric insulation layer and is mounted on any one of the second wiring patterns. Here, at least one of the first inner vias is present in a range that overlaps a range in which the electronic component is present in a lamination direction in which the first wiring patterns are laminated, and has a height in the lamination direction that is smaller than a height of the electronic component.
In a component built-in module that utilizes an existing element having an electronic component mounted on a wiring board, and has an electric insulation layer laminated on the electronic component-mounted surface, it is possible to decrease a height of the first inner via provided substantially opposite to the electronic component in a direction perpendicular to the lamination direction of the first wiring pattern. As a result, even with a decreased diameter of the via, the degradation of reliability resulting from an increase in the aspect ratio is prevented. Therefore, it is possible to provide a component built-in module that has high reliability and is suitable for high-density component-mounting.
Each of the first and second component built-in modules preferably further includes at least one electronic component that is mounted on any one of the first wiring patterns in the plurality of layers, and is not embedded in the electric insulation layer. This provides a component built-in module that has high reliability and is suitable for mounting components at a further higher density.
Furthermore, in each of the first and second component built-in modules, the electric insulation layer preferably is made of a mixture of a filler and an insulating resin. By selecting a type of a filler, it is possible to control a heat conductivity, a coefficient of linear expansion, a dielectric constant, etc. of the electric insulation layer.
In this case, the filler preferably contains at least one selected from alumina, magnesia, boron nitride, aluminum nitride, silicon nitride, tetrafluoroethylene, and silica. This makes it possible to provide an electric insulation layer that is excellent in heat dissipation. In the case where alumina is used as a filler, an advantage of low cost is achieved. The use of magnesia as a filler provides an increase in the coefficient of linear expansion of the electric insulation layer. In the case where boron nitride, aluminum nitride, or silicon nitride is used as a filler, it is possible to decrease the coefficient of linear expansion. The use of tetrafluoroethylene or silica as a filler provides an electric insulation layer having a low dielectric constant.
Furthermore, the insulating resin preferably contains at least one selected from an epoxy resin, a phenol resin, a fluorocarbon resin, a cyanate resin, a polytetrafluoroethylene (PTFE) resin, a poly(phenylene oxide)(PPO) resin, and a polyphenylether (PPE) resin. By selecting an appropriate insulating resin material, it is possible to improve a heat resistance, an electric insulation, and high-frequency characteristics.
In each of the first and second component built-in modules, the first wiring patterns preferably are made of at least one selected from a metal foil, a lead frame, and a conductive resin composition. This allows a fine wiring pattern having a low electric resistance to be formed.
In each of the first and second component built-in modules, the electronic component preferably is a semiconductor bare chip. This allows semiconductor elements to be mounted at a higher density, and since the semiconductor is thinner, this allows the electric insulation layer to have a smaller thickness.
In this case, the semiconductor bare chip preferably is mounted by flip chip bonding. This allows the semiconductor elements to be mounted at a high density.
Furthermore, in each of the first and second component built-in modules, the first inner via preferably is made of a via paste containing a conductive powder and a thermosetting resin. This allows the electric insulation layer and the first inner via to be cured simultaneously, thereby decreasing the number of manufacturing steps.
Furthermore, the wiring board preferably is composed of a ceramic substrate, a glass-epoxy substrate, or a multi-layer substrate having an inner via connection. This configuration allows a component built-in module to be formed using a generally used wiring board, thereby reducing the production cost.
Furthermore, in each of the first and second component built-in modules, the electric insulation layer in contact with the electronic component and the electric insulation layer in contact with the first inner via preferably are provided integrally. The phrase xe2x80x9cprovided integrallyxe2x80x9d herein indicates that the two electric insulation layers have a common composition and are continuous seamlessly. This causes these electric insulation layers to be provided continuously without a boundary, thereby improving the reliability.
Furthermore, in each of the first and second component built-in modules, a plurality of the electronic components preferably are disposed opposite in the lamination direction in which the first wiring patterns are laminated. This allows electric components to be mounted at a higher density.
Furthermore, in each of the first and second component built-in modules, the first wiring patterns preferably include a land pattern electrically connected with the first inner via. This increases an area capable of incorporating electronic components, thereby allowing the same to be mounted at a high density.
A first method for manufacturing a component built-in module according to the present invention includes the steps of: forming a first inner via in an electric insulation layer; mounting an electronic component on a first wiring pattern; and laminating the electric insulation layer and another wiring pattern different from said first wiring pattern in this order on a surface of the first wiring pattern on which the electronic component is mounted so that said first wiring pattern and the another wiring pattern, which are provided opposite each other with the electric insulation layer being interposed therebetween, are electrically connected through the first inner via. Here, the electric insulation layer before being laminated has a thickness smaller than a height of the electronic component in a direction of the lamination.
This allows the first component built-in module of the present invention to be manufactured readily.
In the first method, it is preferable that the another wiring pattern is provided on a surface of another electric insulation layer different from said electric insulation layer, and that the another wiring pattern is connected with an inner via formed in the another electric insulation layer. This facilitates the handling of the another wiring pattern, and allows wiring patterns to be laminated in multiple layers through a decreased number of manufacturing steps.
Furthermore, in the first method the another wiring pattern preferably is carried on a carrier, and the method further includes the step of removing the carrier that is carried out after the laminating step. This facilitates the handling of the another wiring pattern.
Furthermore, in the first method, the another wiring pattern preferably is a second wiring pattern exposed on a surface of a wiring board that includes second wiring patterns in at least two layers, including said second wiring pattern, and a through hole and/or a second inner via that electrically connects the second wiring patterns in different layers with each other. This allows a generally used wiring board having high reliability to be incorporated along with the electronic components.
Next, a second method for manufacturing a component built-in module according to the present invention includes the steps of: forming a first inner via in an electric insulation layer; preparing a wiring board including second wiring patterns in at least two layers, and a through hole and/or a second inner via that electrically connects the second wiring patterns in different layers with each other; mounting an electronic component on the second wiring pattern that is exposed on a surface of the wiring board; and laminating the electric insulation layer and a first wiring pattern in this order on the second wiring pattern on which the electronic component is mounted, so that the second wiring pattern and the first wiring pattern, which are provided opposite with the electric insulation layer being interposed therebetween, are electrically connected through the first inner via. Here, the electric insulation layer before being laminated has a thickness smaller than a height of the electronic component in a direction of the lamination.
This allows the second component built-in module of the present invention to be manufactured readily.
In the second method, it is preferable that the first wiring pattern is provided on a surface of another electric insulation layer different from said electric insulation layer, and that the first wiring pattern is connected with an inner via formed in the another electric insulation layer. This facilitates the handling of the first wiring pattern, and allows wiring patterns to be laminated in multiple layers through a decreased number of manufacturing steps.
Furthermore, in the second method, the first wiring pattern preferably is carried on a carrier, and the method further includes the step of removing the carrier that is carried out after the laminating step. This facilitates the handling of the first wiring pattern.
Furthermore, in each of the first and second methods, the electric insulation layer before being laminated has a hole for accepting the electronic component. This suppresses the displacement of the first inner via when the electronic component is embedded.
In each of the first and second methods, at least a part of the electronic component preferably is embedded in the electric insulation layer upon the electric connection. This allows a component built-in module of the present invention to be manufactured readily.
Furthermore, in each of the first and second methods, the electric insulation layer is cured upon making the electric connection. This allows a component built-in module of the present invention to be manufactured through a decreased number of manufacturing steps.
Furthermore, in each of the first and second methods, it is preferable that at least a part of the electronic component is embedded in the electric insulation layer and the electric insulation layer is cured upon the electric connection. This allows a component built-in module of the present invention to be manufactured through a decreased number of manufacturing steps.
Furthermore, in each of the first and second methods, the electric insulation layer before being laminated preferably is in a non-cured state. This allows an electric insulation layer in contact with the electronic component and an electric insulation layer in contact with the first inner via to be provided integrally, thereby producing a component built-in module of the present invention with high reliability.
Furthermore, in each of the first and second methods, it is preferable that the another electric insulation layer has a wiring pattern on the other surface thereof, and the wiring pattern on the other surface is connected with the inner via of the another electric insulation layer. This causes the inner via formed in the another electric insulation layer to be not exposed, thereby facilitating the handling of the another electric insulation layer, and improving the connection reliability of the inner via.